What diff e34

[D1SL]

Want to swap my welded diff with a 2 way but not sure on which will fit? its a 91 520i e34

[kev.skyline]

youd be better of sticking with the welder, will end up costing you more than you paid for the car id say. im assuming its a winter tramp?
think the 520 would have a medium case diff, any e34 6 cylider diff is the same size but are hard to find. internals out of a medium case e30 or e36 diff will fit your diff, but theyre 250-400 and they will do the job but dont lock great. dave msport rebuilds them and ups the ramp angle to make them lock better but would be more money.

[Smokey Bear]

520i diff is the same as an e30 or an e28. The 525i came with a different subframe even though the diff internal size is the same the casings are different. Waste of time wht ur thinking about doing. I ended up changing to a 525i subframe and diff so I could put an lsd in my e34. Better of sticking with a welder.

[DaveM-sport]

Stick with a welder or do what Smokey did.
Get an E36 M3 3L diff for the internals and use 525i bits to fit it.


E30 LSD bits are the same in size but you can't just use the unit from one inside your diff since the crown-wheel offsets are different due to the 520 having a larger pinion gear (anything 3.46 or below has the large one and anything 3.64 or above usually has the small one)

You could fit the whole E30 LSD unit and cwp no problem but if its being used every day, it'll be a pain to drive as it'll be doing nearly 5K rpm at 60 or 70mph. In saying that, a 3.64 would make an E34 pretty rapid but its not really the point of a 5 series really.